Good number of our snails are protected by the law and honestly they don’t cause any problems for me. But the slugs (Arion vulgaris) are on the rampage in the vegetable patch because it’s part shade, nice, humusy and moist. I don’t dare to mulch in other parts of my garden. Is there any kind of mulch they would avoid?
I figured out they avoid nasturtiums and zucchini plants (I presume they dislike little thorns on their stems).
I sowed lettuce last year just so they would eat it instead of asparagus and, interestingly, tomato leaves.

I heard that saving egg shells and crushing them in small pieces makes it difficult for slugs and snails to slide so they avoid them.

Since I have so many snails I use tuna or salmon small cans that I bury leveled with the ground and I put beer in the cans. The snails are attracted to the hops…I guess and fall in the beer where they drown. I put the cans at dusk and in the morning I find most of them filled up. This can also be done with disposable muffin tins. I cut them individually and place them where I see the most activity. I have a big problem mainly in the summer time since the snails crawl up the siding of my house.